Fastener



FIG. 1 is a top, front, and left isometric view of an ornamental design for a fastener;

FIG. 2 is a left side elevational view of the fastener of FIG. 1;

FIG. 3 is a right side elevational view of the fastener of FIG. 1;

FIG. 4 is a front elevational view of the fastener of FIG. 1;

FIG. 5 is a rear elevational view of the fastener of FIG. 1;

FIG. 6 is a top plan view of the fastener of FIG. 1; and,

FIG. 7 is a bottom plan view of the fastener of FIG. 1.

The broken lines in the drawings depict parts of the article that form no part of the claimed design. 

CLAIM The ornamental design for a fastener, as shown. 